The present invention relates to a cutting apparatus, and more particularly, to a laser cutting apparatus which focuses multiple laser beams on a material to be cut.
Today laser cutting apparatuses and methods for cutting thick materials, such as wood having a thickness greater than one inch or plastic having a thickness greater than two inches, generally involve the use a single high-powered laser which produces a single beam of energy which is directed at the material. The use of a high powered lasers necessitates the use of a long focal length lens which produces a large, undefined focal point on the material, and consequently a wider kerf. The large focal point and wide kerf result in a greater amount of material being vaporized and therefore a slower cut. For some material, such as two inch plexiglass, the cut is almost impossible using a single, conventional laser beam.
Multiple laser beams have been used in a cutting applications, as exemplified by U.S. Pat. No. 4,761,535 to Lawson. Lawson relates to a laser wire stripper which uses a single laser which is directed and focused to a first point, and then directed to a curved reflector where it is refocused to a second point that is displaced from the first point by an amount which permits the insertion of a stripable wire between the two points. The beams cut the wire insulation from alternate sides while the wire is being moved along a line between the two points.
Lawson also discloses a wire cutter apparatus using a single laser which is split into opposing beams by a beam splitter. The opposing beams are directed to opposing sides of the wire and focused at the center of the wire for cutting the insulation from the wire, but not the wire itself. Lawson indicates that the focal points may be moved apart from one another.